The actress, 43, is set to star in Caught in Flight, a film described as "a compelling portrait of Diana, Princess of Wales during the last two years of her life," according to BBC News.

"It is such an honor to be able to play this iconic role," British-born Watts said in a statement. "Princess Diana was loved across the world, and I look forward to rising to the challenge of playing her on screen."

The film – which was previously rumored to feature Jessica Chastain in the lead role – is expected to focus on Diana's romance with heart surgeon Hasnat Khan.